The species which survive well under wide ranges of salinity are called

In the oceans,the environment is perpetually dark at depths of:

$A$ - The salt concentration is less than $5$ (parts per thousand) in inland waters.
$R$ - The salt concentration is $30 - 35$ (parts per thousand) in the sea.

Given below are five statements.
$A.$ Organisms living in oceans,lakes,and rivers also face water-related problems.
$B.$ Euryhaline can tolerate a wide range of salinities.
$C.$ Stenohaline are restricted to a narrow range of salinities.
$D.$ Many freshwater animals cannot live for long in sea water because of the osmotic problems they would face.
$E.$ The salt concentration (measured as salinity in parts per thousand) is less than $5$ in inland waters,$30-35$ in the sea,and $>100$ in some hypersaline lagoons.

Organisms use light as a cue to time their ........... activities.

In which of the following habitats is the variation in soil temperature most significant?